Variable-Gain Amplifier Impedance Switching for Better Return Loss
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Solution Overview
Problem
Wireless communication devices face challenges with existing amplifiers that occupy substantial area due to numerous inductors and components, often resulting in poor return loss in certain operation modes.
Innovation Solution
A variable-gain amplifier with a gain circuit and an impedance circuit that includes an inductor and a switching-capacitive arm, where the switching-capacitive arm can be controlled to change the input impedance based on gain modes, using capacitors and switches to enable or disable paths, thereby adapting impedance for different modes of operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If many inductors and components are used to implement various gain modes, then the amplifier can provide multiple gain modes, but the area occupied on the front-end module increases substantially
Solution Approach 1:
The patent changes the impedance parameter of the amplifier by switching between different capacitor configurations rather than using multiple inductors. The switching-capacitive arm allows the same physical components to provide different impedance values for different gain modes, thereby reducing the area occupied while maintaining adaptability across multiple gain modes.
Solution Approach 2:
The patent makes the switching-capacitive arm serve multiple functions: it provides impedance matching for different gain modes and enables the amplifier to operate in various gain configurations. This single component structure replaces what would traditionally require multiple separate inductor components, achieving multi-functionality with reduced area.
2Adaptability or versatility
If many inductors and components are used to implement various gain modes, then the amplifier can provide multiple gain modes, but the return loss becomes poor in at least one mode of operation
Solution Approach 1:
The patent dynamically changes the capacitive impedance parameter to achieve proper impedance matching for different gain modes. By adjusting the capacitor configuration through the switching mechanism, the amplifier maintains good return loss across all gain modes, avoiding the poor return loss that occurs with fixed inductor-based designs.
3Area of stationary object
If capacitors and switches are used instead of inductors, then the area is conserved and impedance matching is improved, but the device complexity increases due to switching mechanisms
Solution Approach 1:
The patent replaces the mechanical/physical inductor components with an electronic switching-capacitive system. Instead of physically changing inductor configurations, the system uses electronic switches to reconfigure capacitor connections, achieving area reduction while managing complexity through electronic control rather than mechanical reconfiguration.
Data Source
AI summary
Variable-gain amplifiers can include configurable impedance circuits. For example, a variable-gain amplifier can operate in a plurality of gain modes to amplify a signal with different levels of amplification. The variable-gain amplifier can include a gain circuit configured to amplify a signal and an impedance circuit coupled to the gain circuit. The impedance circuit can include an inductor and a capacitive arm coupled in parallel to the inductor. The impedance circuit can operate based on a current gain mode to change an impedance for the variable-gain amplifier. For example, the capacitive arm can be controlled to change inductance for the different gain modes of the variable-gain amplifier.